Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F03—MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
  • F03D—WIND MOTORS
  • F03D1/00—Wind motors with rotation axis substantially parallel to the air flow entering the rotor 
  • F03D1/06—Rotors
  • F03D1/065—Rotors characterised by their construction elements
  • F03D1/0675—Rotors characterised by their construction elements of the blades
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F03—MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
  • F03D—WIND MOTORS
  • F03D80/00—Details, components or accessories not provided for in groups F03D1/00 - F03D17/00
  • F03D80/30—Lightning protection
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
  • F05B—INDEXING SCHEME RELATING TO WIND, SPRING, WEIGHT, INERTIA OR LIKE MOTORS, TO MACHINES OR ENGINES FOR LIQUIDS COVERED BY SUBCLASSES F03B, F03D AND F03G
  • F05B2280/00—Materials; Properties thereof
  • F05B2280/60—Properties or characteristics given to material by treatment or manufacturing
  • F05B2280/6003—Composites; e.g. fibre-reinforced

Definitions

• a method for the manufacturing of a wind turbine blade comprises providing a blade mold with a mold cavity and arranging fibre material in the mold cavity. The method further comprises arranging a first electrically conductive layer along a longitudinal direction of the wind turbine blade. A spar cap is arranged over the first electrically conductive layer. Furthermore, the method comprises arranging a second electrically conductive layer over the spar cap. The method also comprises electrically connecting the first electrically conductive layer and the second electrically conductive layer.
• a method that enables manufacturing a wind turbine blade with enhanced internal protection against lightning strikes, which may cause punctures to the external shell of the rotor blade and attach the carbon fiber or glass fiber spar cap directly.
• the manufacturing method provides improved electromagnetic field control of the spar cap of the blades in a simple manner and with a limited number of manufacturing steps.
• the method according to this aspect of the disclosure can be integrated in the manufacturing of wind turbine blades comprising different materials. More specifically, the process is applicable to blades comprising glass fiber and/or carbon fiber based spar caps. Furthermore, the method can be implemented for the manufacture of wind turbine blades comprising pultruded pieces.
• Fig. 1 illustrates a conventional modern upwind wind turbine 2 according to the so-called "Danish concept" with a tower 4, a nacelle 6 and a rotor with a substantially horizontal rotor shaft.
• the rotor includes a hub 8 and three blades 10 extending radially from the hub 8, each having a blade root 17 nearest the hub and a blade tip 14 furthest from the hub 8.
• Fig. 2A shows a schematic view of an example of a wind turbine blade 10.
• the wind turbine blade 10 has the shape of a conventional wind turbine blade with a root end 17 and a tip end 15 and comprises a root region 30 closest to the hub, a profiled or an airfoil region 34 furthest away from the hub and a transition region 32 between the root region 30 and the airfoil region 34.
• the blade 10 comprises a leading edge 18 facing the direction of rotation of the blade 10, when the blade is mounted on the hub 8, and a trailing edge 20 facing the opposite direction of the leading edge 18.
• the airfoil region 34 (also called the profiled region) has an ideal or almost ideal blade shape with respect to generating lift, whereas the root region 30 due to structural considerations has a substantially circular or elliptical cross-section, which for instance makes it easier and safer to mount the blade 10 to the hub 8.
• the diameter (or the chord) of the root region 30 may be constant along the entire root region 30.
• the transition region 32 has a transitional profile gradually changing from the circular or elliptical shape of the root region 30 to the airfoil profile of the airfoil region 34.
• the chord length of the transition region 32 typically increases with increasing distance from the hub 8.
• the airfoil region 34 has an airfoil profile with a chord extending between the leading edge 18 and the trailing edge 20 of the blade 10. The width of the chord decreases with increasing distance from the hub to the tip.
• a shoulder 40 of the blade 10 is defined as the position, where the blade 10 has its largest chord length.
• the shoulder 40 is typically provided at the boundary between the transition region 32 and the airfoil region 34.
• chords of different sections of the blade normally do not lie in a common plane, since the blade may be twisted and/or curved (i.e. pre-bent), thus providing the chord plane with a correspondingly twisted and/or curved course, this being most often the case in order to compensate for the local velocity of the blade being dependent on the distance to the hub.
• the wind turbine blade 10 comprises a blade shell comprising two blade shells (also referred to as shell parts, half shells or blade halves), a first blade shell part 24 and a second blade shell part 26, typically made of fiber-reinforced polymer.
• the wind turbine blade 10 may comprise additional shell parts, such as a third shell part and/or a fourth shell part.
• the first blade shell part 24 is typically an upwind, windward or pressure side shell part.
• the second blade shell part 26 is typically a downwind, leeward or suction side blade shell part.
• the first blade shell part 24 and the second blade shell part 26 are fastened together with adhesive, such as glue, along bond lines or glue joints 28 extending along the trailing edge 20 and the leading edge 18 of the blade 10.
• the root ends of the blade shell parts 24, 26 have a semi-circular or semi-oval outer cross-sectional shape.
• Fig. 2B is a schematic diagram illustrating a cross sectional view of an example of a wind turbine blade 10, e.g. a cross-sectional view of the airfoil region of the wind turbine blade 10.
• the wind turbine blade 10 comprises a leading edge 18, a trailing edge 20, a pressure side shell part 24, a suction side shell part 26, a first spar cap 74, and a second spar cap 76.
• the wind turbine blade 10 comprises a chord line 38 between the leading edge 18 and the trailing edge 20.
• the wind turbine blade 10 comprises one or more shear webs 42, such as a leading edge shear web and a trailing edge shear web.
• the shear webs 42 could alternatively be a spar box with spar sides, such as a trailing edge spar side and a leading edge spar side.
• the spar caps 74, 76 extending in a substantially spanwise direction within the blade 10, may comprise glass fibers, hybrid fibers or carbon fibers while the rest of the shell parts 24, 26 may comprise glass fibers.
• the spar caps 74, 76 may be part of, i.e. may be integrally formed, or they may be adhered to the respective blade shells.
• each shell part 24, 26 may comprise one or more additional spar caps.
• Method 100 comprises, at block 110, providing a blade mold 11 comprising a mold cavity. Fiber material is arranged in the mold cavity in block 120. Subsequently, a first electrically conductive layer 61 is arranged along a longitudinal direction of the wind turbine blade 10 in block 130. A spar cap 74 is arranged over the first electrically conductive layer 61 in block 140. The method then comprises, in block 150, arranging a second electrically conductive layer 62 over the spar cap 74.
• first electrically conductive layer 61 and the second electrically conductive layer 62 are electrically connected in block 160, thus forming a "sandwich-like" or stack structure in which the spar cap 74 is at least partially arranged in the space between the first electrically conductive layer 61 and the second electrically conductive layer 62.
• the first electrically conductive layer 61 and/or the second electrically conductive layer 62 may comprise semiconductive materials, e.g. graphene or semiconductive coatings. Furthermore, electrically connecting the first electrically conductive layer 61 and the second electrically conductive layer 62 in block 160 may comprise that the layers are galvanically connected, i.e. that a direct physical contact is established between them.
• arranging a spar cap 74 over the first electrically conductive layer 61 may comprise, in an example, directly placing the spar cap 74 on the first electrically conductive layer 61 so that a direct physical contact is established between the first electrically conductive layer 61 and a surface of the spar cap 74.
• an intermediate material e.g. one or more layers of fiber material, may be arranged between the first electrically conductive layer 61 and the spar cap 74.
• Figure 5A shows an initial stage in which fiber material 51, e.g. glass fibers or carbon fibers, may be arranged inside the cavity of the blade mold 11.
• Figures 5B and 5C show the arrangement of the first electrically conductive layer 61 and the spar cap 74, respectively.
• the spar cap 74 is also directly positioned on the first electrically conductive layer 61.
• the width of the first electrically conductive layer 61, W1 may be larger than the width of the spar cap 74, W SP . In this manner, electromagnetic shielding of the spar cap 74 may be enhanced.
• filling material 53 including, e.g.
• the first electrically conductive layer 61 and the second electrically conductive layer 62 may be electrically connected via at least one of the following: soldering, welding, bolts, rivets, fasteners, conductive glue or conductive adhesive.
• the electrically connected layers 61, 62 may be then connected to the lightning receptors 81 and/or to an external conductive mesh arrays of the air termination system.
• the spar cap 74 may comprise a plurality of electrically conductive projections 75 arranged at different positions along the length of the spar cap 74. Said projection may protrude from the spar cap 74 in a direction substantially along a local chord line towards the trailing or leading edge (as required by the blade design).
• the first electrically conductive layer 61 and the second electrically conductive layer 62 may be electrically connected at said electrically conductive projections 75.
• the electrically conductive projections 75 are represented in Figure 4C .
• first, second, third and fourth electrically conductive layers is simply used to explain that, in this case, four different electrically conductive layers may be arranged. Under no circumstance, should this wording be interpreted as implying any kind of sequence between the layers.
• both spar caps 74, 76 of the wind turbine blade 10 may be electrically shielded by the corresponding electrically conductive layers 61-64. Furthermore, by electrically connecting the electrically conductive layers 61-64 to the air termination system, an equipotential connection may be provided between the spar caps 74, 76, thus reducing the risk of arcing and any unwanted electrical discharge.
• FIGs 7A and 7B illustrate a blade 10 wherein both spar caps 74, 76 are shielded by the corresponding electrically conductive layers 61-64. As mentioned above, Figure 7B illustrates an example further comprising an additional down conductor 82.
• At least some of the elements of the air termination system may each be electrically connected to the electrically conductive layers 61, 62 of a first spar cap 74 and/or to the electrically conductive layers 63, 64 of a second spar cap 76.
• electrical connection between the lightning receptors 81 and the conductive layers 61-64 may be provided via a first set of conductors 91, which may comprise metallic conductors, e.g. cables or plates.
• each of the lightning receptors 81 may be electrically connected to the electrically conductive layers of both spar caps 74, 76.
• the down conductor 82 may be configured to extend along the length of the blade 10.
• the down conductor 82 may be attached to one or more shear webs 42, as schematically depicted in Figure 7B .
• multiple arrangements may be provided to enable electrical connection between the lightning receptors 81, the electrically conductive layers 61-64 and the dedicated down conductor 82.
• Figure 7B shows a blade 10 wherein a first set of conductor elements 92 may be used to connect the lightning receptors 81 to the down conductor 82, whereas a second set of conductor elements 93 may be used to electrically connect the electrically conductive layers 61-64 to the down conductor 82.
• the down conductor 82 may be directly connected to the lightning receptors 81 and to the electrically conductive layers 61-64.
• FIGS 7C-7E schematically depict some further examples applicable to systems wherein both spar caps 74, 76 comprise electrically conductive layers.
• a direct electrical connection may be established between the electrically conductive layers 61, 62 of one spar cap 74 and the electrically conductive layers 63, 64 of the other spar cap 76.
• Figure 7C shows a similar example to the one depicted in Figure 7B .
• conductor elements 93 of Figure 7B may be replaced by a new set of conductor elements 95.
• Conductor elements 95 may be provided to directly connect both spar caps 74, 76 and they may be guided along the shear web 42. Such direct connection may provide an improved equipotentialization of the system.
• Conductor elements 95 may be embodied as cables, wires, metallic plates, conductive paints, etc. Specifically, conductor elements 95 may be flexible to provide a better fixation and guiding on the shear web 42. Furthermore, multiple conductor elements 95 may be provided at different locations along the length of the blade 10.
• a dedicated lightning down conductor 82 may also be present, which may be connected to both the air termination system, e.g. the lightning receptors 81, and to the conductor elements 95.
• conductor elements 95 may also be provided to electrically connect the electrically conductive layers 61-64 of both spar caps 74, 76 as previously shown with reference to Figure 7C .
• a set of conductors 96 may be employed to connect the air termination system, e.g. the lightning receptors 81, on each of the pressure or suction side to the corresponding spar caps 74, 76.
• Such conductors 96 may be arranged along the inner surface of the blade shells as schematically depicted in Figure 7D .
• conductors 96 may comprise flexible metallic films, cables, wires or electrically conductive paints.
• Figure 7D may provide advantages due to the fixation of both conductors elements 95, 96 to structural parts of the wind turbine blade, i.e. to the shear web 42 or blade shells. In this manner, a more reliable and stable connection may be provided while preventing the presence of conductor elements within the body shell of the blade 10.
• Figure 7E Still a further example is provided in Figure 7E .
• This example may be understood as a combination of examples shown in Figures 7A and 7D .
• the same type of conductors 95, 96 may be arranged to establish an electrical connection between the electrically conductive layers 61-64 of both spar caps 74, 76 and with the air termination system, e.g. with the lightning receptors 81.
• no dedicated down conductor 82 may be provided in this variant.
• at least one of the electrically conductive layers 61-64 may be electrically connected to the ground. In this manner, said at least one electrically conductive layers 61-64 may act as a down conductor, thus receiving the lightning current from the air termination system and directing it to the ground of the wind turbine 2.

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• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
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Citations (6)

• 2024
  • 2024-01-12 EP EP24151710.1A patent/EP4585800A1/fr active Pending
• 2025
  • 2025-01-10 WO PCT/EP2025/050593 patent/WO2025149647A1/fr active Pending

Patent Citations (6)

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